Homeland security-related companies have seen a 91 percent first-quarter profit gain and a 4.1 percent profit margin gain since the Sept. 11 attacks, making them one of the fastest-maturing sectors in the market, according to the latest Barron's.

The companies all have roles in protecting airports and airlines or with access control for buildings and/or computer systems.

The stock values have risen in conjunction with the creation of the Department of Homeland Security and the continuing expectation of a steady stream of government revenue.

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